Fluid-tight insulated wall devices and applications thereof



I LEAU TED W DEVICES AND ONS THEREOF 2 Sheets-Sheet l AT. LT A C T. lL J P. TD.. HA G I T D rl. U L F 5 6 9 l OO 6 4 9 2 1 e m 2 J n d n a .l J F Illu l. Il lill-lah.-

.nvm/rm JEAA/ A L .EAU/1 E MME @N Q A WoW/5v5 J. ALLE Jan. 2, 1968 AUME FLUID-TIGHT INSULATED WALL DEVICES AND APPLICATIONS THEREOF Filed June 24, 1965 2 Sheets-Sheet 2 Ammvflfl Dn/mrow YEA/V LLEUME ./By: /Vffle United States Patent O 3,361,285 FLUID-TIGHT HNSULATED WALL DEVICES AND APPMCATIGNS THEREUF Jean Alleaume, Saint Cloud, France, assigner to Technigaz, Paris, France, a corporation of France Filed lune 24, 1965, Ser. No. 466,626 Claims priority, application France, .lune 27, i964,

13 claims. icl. 22e-9) -mmm.

ABSTRACT OF THE BISCLGSURE A fluid storage heat-insulated container wall construction comprising from inside towards outside: one primary, fluid-coniining, inner, impervious, flexible, barrier sheet; at least one secondary impervious, flexible, 'barrier sheet, said primary and secondary barrier sheets being applied against each other; at least one layer of insulating material supporting said primary and secondary barrier sheets and adjacent to the outer face of said secondary barrier sheet; connecting means for fastening said barrier sheets to said insulating material and adapted to hold said barrier sheets against relative motions; and an outer carrying structure supporting said insulating material which is secured thereto.

The present invention has essentially for is object a device constituting a continuous, duid-tight and insulated wall, as well as its various applications.

In the present known state of the art, multiple-layer or stratiforrn walls of this character have al-ready been provided for constructing enclosures or tanks for storing, preserving, accumulating or transporting a liquid or gaseous fluid, which are of the type comprising at least one internal fluid-tight envelope called primary barrier, which actually contains the fluid in question, preferably at least one complementary fluid-tight enternal envelope constituting a secondary barrier which for example may be substantially parallel to said rst barrier so as to surround or enclose same at least partially, and one or a plurality of layers of insulating materials acting as support means to said barriers, said layers consisting respectively of an assembly of juxtaposed imprevious or like elements such as thin metal sheets, plates, membranes, etc. As a rule, these two respectively primary and secondary barriers are spaced from each other `by providing therebetween an intermediate gap advantageously filled with a layer of insulating materials supporting the primary barrier applied against said layer, the latter either supporting the secondary barrier applied against the opposite face of said layer or being applied directly against said secondary barrier, the latter being supported in turn by an external structure to which said secondary barrier is secured with the interposition, if desired, of another intermediate insulating layer. Thus, the wall assembly constitutes, when seen in section, a kind of sandwich.

In these known constructions the fastening of the respectively primary and secondary barriers on or against the insulating support is frequently attended by the inconvenience of an insufficient or precarious mechanical resistance to tearing stress, that is, in `a direction at right angles to the sheets or plates, and to mutual creeping movements, that is, in a direction tangent to the contacting surfaces. Moreover, and particularly in the specific case of the cryogenic preservation of iiuids cooled to very low temperatures, for example liquefied natural gases such as methane, the relative spacing of these respectively primary and secondary barriers causes these barriers to have different temperatures, since the primary barrier adjacent to the liquid contained in the enclosure 3,36L285 Patented dan. 2, i963 ICC or tank will have substantially the same very low temperature as the fluid, whereas the secondary barrier will be at a higher temperature. This temperature differential is objectionable, if not as a risk or danger in itself, in that it promotes the sudden vaporisation of the enclosed liquefied gas in case of leakage of the confined iiuid through the primary barrier, into the space provided between the two barriers, in case of insufiicient fluid-tightness of said primary barrier, and therefore the generation of an overpressure likely to tear ofi or at least cause the sheets or plates constituting said barriers to swell or buckle. Finally, in previously known systems and construction, the volume or quantity of dry inert gas such as nitrogen which is generally introduced and kept therein under relative overpressure conditions (in relation to the surrounding atmosphere) may be relatively considerable due to the aforesaid importance of the intermediate space involved, notably in the case of tanks of relatively large size.

It is within the scope of the present invention to eliminate or palliate the inconveniences set forth hereinabove, and with this end in view the wall-forming device according to this invention is remarkable notably in that the aforesaid primary and secondary barriers respectively are applied against or superposed to each other, so as to be in direct mutual contact, and that theyv engage said adjacent insulating layer with the outer face of said secondary barrier which comprises means for attachment or connection to said insulating layer, said means being adapted to hold said barriers against motion respectively in the normal tearing directions and tangent slipping directions. The chief advantage of this arrangement is that the secondary barrier is at substantially the same temperature as the primary barrier, so that no sudden or very rapid vaporization of the liquefied gas can take place in case of leakage through the primary barrier into the separation gap or space. 0n the other hand, said primary and secondary barriers are frequently made of relatively thin and flexible, corrugated, pleated or like waved sheets or plates, in order to impart thereto the flexibility necessary to permit their free deformation by thermal expansion or contraction, so that in the case of primary and secondary barriers having their corrugations substantially symmetrical with respect to the plane of separation of said barriers, and if these corrugations register substantially with one another, the intermediate space available between said barriers and constituted by pairs of adjacent corresponding corrugations of each vbarrier is relatively small and therefore, for a given sensitivity of the leakage detecting apparatus, it will be casier to trace leakages. Moreover, the channels constituted by these substantially tubular spaces bounded by the registering waves of said sheets or plates will facilitate the eduction of vapors likely to be formed therein, thus eliminating any risk of relatively high local overpressures likely to cause the tearing of said sheets or plates. Finally, at the same time the volume of inert gas which is necessary for filling said intermediate space or gap is reduced proportionally.

According to another feature characterizing this invention, the aforesaid attachment or connecting means consist of a plurality of fastening members constituting anchoring, sea-ling or like blocks, rigid with, and in fluidtight relation to, the outer face of said secondary barrier, said fastening members being distributed over the entire area of said face and projecting externally therefrom; said blocks are fitted, embedded, fixed or set in the aforesaid adjacent insulating layer and comprise on the one hand retaining means for holding said insulating layer and on the other hand means for fastening said primary barrier.

According to a further feature `of this invention each anchoring block aforesaid is of substantially cylindrical, conoidal, prismatoidal or pyramidal composite configuration with the free end or base 1provided with at least one substantially sidewise projecting portion forming a flange, ledge, shoulder, collar or the like, constituting said holding means.

According to another lfeature of this invention, each anchoring block aforesaid comprises a blind tapped hole or the like having its axis disposed preferably substantially centrally of or coaxially with said block and perpendicular to said secondary barrier, said hole opening on the side of said barrier and registering on the one hand with a conresponding orifice formed therein and on the other hand with another corresponding orifice formed in said primary barrier which covers said secondary barrier and is tightly clamped by means of a screw or the like extending through said orifices and engaging said tapped blind hole.

According to another feature of this invention each local fastening, yfor example by means of screws, of said primary barrier is concealed or covered in a duid-tight manner on the inner side either by a primary barrier sheet-metal element, connected along its edge by a fluidtight lap joint, for example a lap joint welded to said primary ybarrier sheet-metal element held by said screw fastening means, or by a preferably ldomed cap or the like fitting over said fastening zone and secured by a duidtight peripheral joint, notably a welded joint, on the inner face of said primary lbarrier.

The present invention is also concerned, by way of novel industrial products, with said anchoring blocks designed for fastening said barriers.

The present invention also contemplates the method of manufacturing fluid-tight walls of the type set forth hereinabove which results from the construction of these walls.

Finally, the present invention is concerned more particularly with tanks, vats, cisterns, caissons, reservoirs, holds, bunkers, chambers or the like, constructed by using walls of the type set forth hereinabove, and notably tanks of the -so-called integrated or built-in type forming an integral part either of the hull of ships, or of the sup-porting structure of fixed or movable installations.

Other features and advantages of this invention will appear as the following detailed description proceeds with reference to the diagrammatic drawings attached hereto, given by way of example and illustrating typical forms of embodiment of this invention. In the drawings:

FIGURE l is a fragmentary sectional view taken across the thickness of a wall constructed according to the teachings of this invention, showing the fastening of the primary and secondary barriers to the layer of insulating material, in the vicinity of a lap joint between two sheets or plates constituting the primary barrier;

FIGURE 2 is a view similar to FIGURE l but showing a fastening point lying `outside the zone of an overlapping joint;

FIGURE 3 is a similar axial section showing an alternate form of embodiment `of an insert member;

FIGURE 4 is a similar view showing another alternate form of embodiment of a lfastening point utilizing a hollow bolt;

FIGURE 5 illustrates another modification of the fastening block or bolt with separate or insert head, and

FIGURE 6 is a fragmentary sectional view showing one portion of a wall of a tank integrated in the hull of a ship, utilizing barriers made of corrugated sheets or plates.

In the exemplary form of embodiment illustrated in FIGURE l the reference numeral l designates a lagging or heat-insulating layer constituting for example a sandwich consisting of cellular, expanded or like material 2, such as foam material, interposed between two plywood or wooden layers 3. Of course, any other type of solid, synthetic or natural insulating material, whether of compact, massive or pulverulent type, may be used to this end. This insulating layer is supported by any suitable surrounding structure Il. The plywood or equivalent layer 3 adjacent to the barriers may of course be connected to he structure 4 through any other suitable means such as studs, cleats, tie-rods, strips, or the like, preferably of insulating material such as compressed wood.

The secondary barrier 5 consisting of a preferably thin and flexible plate or sheet material has its outer surface applied against the inner face of the insulating layer, that is, in the case of the example illustrated, on the plywood layer 3. rPhis secondary barrier 5 is fastened at'each fastening point contemplated to the aforesaid insulating layer l by means of an anchoring block or like memer 6 which is preferably rigidly connected or bonded to the outer face of said sheet or plate material 5 and embedded inthe insulating layer by being fitted in a corresponding cavity 7 thereof. The secondary barrier, like the primary barrier, is preferably metallic and consists for example of stainless steel, and the anchoring block 'd is also metallic.

This anchoring block t5 may be an integral part of the secondary barrier 5, for example by being formed integrally therewith, but an advantageous construction consists in securing this secondary barrier by fluid-tight welding on the front or end face E5 of said block which is substantially flush with the inner face of said insulating layer I. To this end, the sheet metal `element 5 has formed therein at each fastening point a port or aperture 9 and the sheet element 5 is secured by means of a fluid-tight weld seam itl connecting the edge of this aperture to the front face S of block 6. Tlhis block o may have any suitable shape preferably a cylindrical or plrismatic shape, and comprises at its end embedded in the insulating layer ll a projecting portion Il constituting a preferably sidewise yprotruding flange, ledge or head in onder to lock said block against `motion substantially in its axial direction within the insulating layer. The length of said cylindrical or prismatic body of said block 6 may be for example at least equal to the thickness of the plywood layer through which it extends, whereby the stop-forming ange 1l is embedded in the layer of insulating material filling the space between the two plywood layers, the cavity 7 of said block 6 accomodating exactly or conforming to the contour of the outer surface of said block.

Each anchoring block 6 comprises at least one substantially longitudinal tapped blind hole 12 disposed preferably centrally of or coaxially with said block and opening on the inner end face S thereof, this face being for example substantially flat. The edge 13 of this blind hole l2 is advantageously countersunk bevelled or chamfered.

The primary barrier i4 consists as a rule, like the secondary barrier, of a plurality of juxtaposed sheets or plates such as the pair of adjacent sheets 14a and 14b connected or welded to each other along a fluid-tight lap joint 15 disposed on the inner face of the primary barrier. This primary barrier ill is in direct Contact with the secondary barrier 5.

Each portion 14a of the primary barrier 14 which is in contact with the underlying secondary barrier 5 is secured to each anchoring block 6 aforesaid by means of a screw 16 preferably of the fiat-head or countersunk type which extends through a hole ll7 formed with flanged edges in the sheet 14a, a washer or like member 18 preferably of the dished or cupped type being interposed therebetween.

If the anchoring block 6 is located in the vicinity or proximity of a lap point 15 aforesaid the sheet element or portion i412 of the primary barrier 14 will advantageously cover the screw head lo as well as the surrounding portion whereby the screw head is concealed and the screw fastening completely isolated, concealed and protected from the outside in a fluid-tight manner,

If an anchoring block 6 were located outside of or remote from a lap joint such as 15 the screw fastening could be covered and insulated in a fluid-tight manner by using a cap 19 or like member of a size greater than the orifice 9 formed in said secondary barrier and preferably welded thereto along its peripheral edge as at 20, to provide a sealed assembly as shown in FIGURE 2. To reduce stress in the marginal portions and the weld seams along the edge of said cap 19, the latter is preferably domed with the concavity turned towards the fastening screw.

The proper welding of the secondary barrier on each -anchoring block 6 necessitates a perfect engagement or matching -between said barrier and said block, this requirement being in certain cases difficult to meet or necessitating a more or less long time. To avoid this diiculty and according to another form of embodiment, illustrated in FIGURE 3 of the drawing, the secondary barrier 5 is secured to each anchoring block 6 by means of a screw having a special shape and extending through a corresponding orifice formed in said secondary barrier 5, the head of this special screw urging or clamping said secondary barrier against said block `6 and being welded to said barrier along the edge of said head. This special screw consists of an externally screw-threaded insert member 21 engaging a corresponding tapped blind hole 12a formed in each block 6a. Each insert member 21 comprises a head or like portion 22 which may be either formed integrally therewith or added thereto, and adapted to press against the end face of said lblock 6a the edge of the corresponding orifice 9a formed in said secondary barrier 5 and interposed between said head and said face of block 6a. The fluid-tight assembly between the peripheral edge of head 22 and the secondary barrier 5 consists preferably of a continuous weld seam 23.

Each insert member 21 has a substantially coaxial blind tapped hole 24 formed therein for receiving the screw 16 securing the primary barrier 14.

Of course, the fluid-tight sealing of the joints by welding `may be replaced by any other continuous assembly method, such as soldering, luting, cementing, gluing or the like.

FIGURE 4 illustrates a modified form of embodiment of said fastening means wherein each -anchoring block 6b constitutes a kind of bolt in which said taped blind lhole 12 is formed and comprising a body or shank 2S of which the end embedded in the insulating material 1 is formed with external screw-threads, a nut-forming plate or like element 26 for example of square configuration being screwed on said end to constitute the aforesaid retaining means corresponding substantially to the aforesaid flange 11 of FIGURE l. At its opposite end the body is provided with a head or like portion 27 which may ybeeither inserted thereon or formed integrally therewith, this head pressing the inner face of the secondary barrier 5 and having preferably its peripheral edge welded thereon at 28. l

While the head 27 shown in FIGURE 4 is formed integrally with the body 25 of anchoring block 6b, in the alternative form of embodiment illustrated in FIGURE 5 it consists of a washer or like member 27a inserted on the aforesaid body 2S for example by being force tted thereon and welded as at 29.

FIGURE 6 illustrates atypical example of a wall structure according to this invention, as applied to the construction of a tank forming an integral part of the hull structure of a ship of which the planking designated by the reference numeral 30 constitutes the structure carrying the insulating layer 1 secured through suitable means to the inner wall or face of said hull. The two contig-uous barriers, respectively the primary barrier 14 and the secondary barrier 5, comprise in this case corrugations such as 31 and 31 extending at least along two perpendicular directions and disposed preferably in such a manner that one wave 31 of the primary barrier 14 has its concavity turned towards the secondary barrier 5 and registers substantially with the trough of a corresponding corrugation of said secondary barrier. Due to the provision of these corrugations, notably on the secondary barrier where their convexity is turned towards the insulating layer 1, it is necessary to interpose between said secondary barrier 5 and said insulating layer 1 intermediate insulating supports such as 32 comprising hollow recesses or impressions 33 adapted to receive with a suitable clearance the projecting or relief portion or waves of the outer face of said secondary barrier, whereas between said cavities these insulating supports 32 accommodate or conform to the contour of the surface, for example a flat surface, extending between two successive corrugations of said secondary barrier. These supports are advantageously secured to the insulating layer 1 by means of anchoring blocks 6 of the type set forth hereinabove, to which they are fastened directly `by means of screws extending therethrough and engaging taped holes 12 formed in said blocks.

The fastening of the respectively secondary and primary barriers 5, 14 on the insulating supports 32 is effected in a manner similar to that shown in the preceding iigures, by using other anchoring blocks 34 substantially similar to the aforesaid anchoring blocks 6 and fitted in said supports 32, these other blocks 34 being mounted in recesses formed in said supports and provided with adequate countersunk cavities.

The insulating supports 32 may consist for example of studs of compressed wood, lamellar wood or similar wood, compos-itions, and they are yadapted to be secured on the insulating layer 1 through any other means having an eiiiciency equivalent to that resulting from the use of said anchoring blocks.

Of course, this invention should not be construed as being Ilimited by the specific forms of embodiment shown and described herein by `Way of example since many modifications may be brought thereto without departing from the scope of the invention as set forth in the appended claims.

What I claim is:

1. A fluid-tight thermally insulating wall construction for a container for storing a fluid, successively comprising from inside towards outside: one primary inner fluid-tight tlexible metal barrier sheet means for confining said fluid; -at least one secondary fluid impervious and relatively thin exible metal barrier sheet means, said primary and secondary barrier sheet means being tightly applied against each other in mutually direct engaging relationship substantially throughout their whole surfaces; at least one layer of load-bearing and transmitting insulating material fully supporting said primary and secondary barrier sheet means which are yieldable under pressure and adjacent to the outer face of said secondary barrier sheet means which is `applied thereagainst over substantially its whole surface; connecting means for fastening said barrier sheet means at a plurality of discrete locations to said layer of insulating material and adapted to hold said barrier sheet means against relative motions in the normal tearing direction `and in theA tangential sliding direction, respectively; and an outer self-carrying structure for supporting said layer of insulating material which is attached thereto.

2. A device according to claim 1, wherein said connecting means comprise a plurality of spaced anchoring block members integral in sealing relationship with and projecting from the outer face of said secondary barrier sheet means, said anchoring block members being embedded in said layer of insulating material and including retaining means for locking and holding said anchoring block members in said insulating material; and attachment means for fastening said primary barrier sheet means to said anchoring block members.

3. A device according to claim 2, wherein each anchoring block member is formed with a shank portion snugly fitted in a corresponding bore provided in said insulating material and integral at its outer end with a peripheral radially outward projecting ange portion forming said retaining means whereas the inner end of said shank portion i.e. which is opposite to said ange portion is rigidly connected to said secondary barrier sheet means which is formed with a hole substantially coaxial with said bore, said shank portion being formed lengthwise thereof with at least one threaded blind hole opening in the end face of the inner end of said shank portion to receive one headed screw extending through a relevant orice of said primary barrier sheet means and through said hole in said secondary barrier sheet means and constituting said attachment means.

4. A device according to claim 3, wherein at least said primary barrier sheet means consists of a plurality of sheet elements juxtaposed and connected to each other in overlapping sealing relationship along duid-tight joints consisting each one of an underlying edge portion of one sheet element and of an overlying edge portion of an adjacent sheet element, covering said underlying edge portion and wherein the screws of the anchoring block members which are located in the vicinity of said joints extend only through the underlying edge portions thereof so that their heads are covered by said overlying edge portions, whereas the screws of the anchoring block members which are remote from said joints, have their heads covered by a cap peripherally attached in sealing relationship to the inner face of said primary barrier sheet means.

5. A device according to claim 4, wherein the inner end face of each anchoring block member is in flush relation to the inner face of said layer of insulating material and the edge of each hole in said secondary barrier sheet means is applied in overlapping relationship against the inner end face of the associated anchoring block member and welded thereto so as to form a continuous seam.

6. A device according to claim 4, wherein the inner end face of each anchoring block member is in flush relation to the inner face of said layer of insulating material and said threaded blind hole receiving said headed screw is provided in a headed threaded insert screwed in a corresponding tapped blind hole of said anchoring block member, the edge of each hole in said secondary barrier sheet means being applied in overlapping relation against the inner end face of the associated anchoring block member so as to be clamped between the latter and the head oi said threaded insert, and said head being peripherally welded to said secondary barrier sheet means.

7. A device according to clairn 4, wherein the shank portion of each anchoring block member extends through said hole in said secondary barrier sheet means to terminate in a head portion overlapping the edge of said hole so as to press said edge against said layer of insulating material, said head portion being lperipherally welded to said secondary barrier sheet means and the ange portion of said anchoring block member consisting of an inside threaded nut-like washer plate screwed on the outer end of said shank portion and embedded in said insulating material.

8. A device according to claim 4, wherein said primary and secondary barrier sheet means are formed with space apart corrugations respectively in such a manner that the corrugations of said primary barrier sheet means project only inwards therefrom and the corrugations of said secondary barrier sheet means project only outwards therefrom, the corrugations of said primary and secondary barrier sheet means being in registering relation to each other, whereas said insulating material comprises on the one hand an inner layer of supporting parts which are adjacent to and complementary of the outer corrugated face of said secondary barrier sheet means so as to conform thereto in shape, said anchoring block members being embedded in said inner layer, and on the other hand of an outer continuous layer to which said inner layer is fastened by further connecting means comprising further anchoring block members embedded in said outer layer and headed screws extending through said supporting parts and screwed in said further anchoring block members.

9. A device according to claim 4, wherein said layer of insulating material comprises at least one sandwich-like assembly consisting of an inner layer of plywood, an outer layer of plywood and at least one intermediate layer of insulating material, the flange portions of said anchoring block members being embedded in said intermediate layer of insulating material.

10. A device according to claim 4, wherein said outer self-carrying structure is formed by the hull proper of a transport vehicle.

11. A device according to claim 8, wherein said corrugations are spaced by and dene therebetween smooth uncorrugated areas and said connecting means are located under such areas to fasten them to the insulating material.

12. A device according to claim 4, wherein each headed screw has a flat countersunk head and the corresponding hole in that primary barrier sheet element through which said screw extends is hanged to provide an outward creased edge received in a complementary countersunl; portion of the blind hole formed in the associated anchoring block member, whereby said flanged hole accommodates the screw head so that its top face does not project inwards rorn said sheet element.

13. A device according to claim 4, wherein said layer of insulating material comprises at least one sandwichlike assembly consisting of two respectively inner and outer board-like layers of a relatively rigid material and of at least one intermediate layer arranged therebetween, the ilange portions of said anchoring block members being embedded in said intermediate layer.

References Cited UNlTED STATES PATENTS 1,620,415 3/1927 Van Orman 220-9 2,106,840 2/1938 Gould 220-9 2,306,275 12/1942 Murray 22015 2,892,563 6/1959 Morrison 220-15 3,003,810 10/1961 Kloote et al. 220-9 3,030,669 4/1962 Doslier 220-10 3,079,026 2/1963 Dosker 2120-9 3,088,621 5/1963 Brown 220-9 3,122,000 2/1964 Siracky 220-9 3,150,793 9/1964 Messer 220-9 3,151,416 10/1964 Eakin et al 220-9 THERON E. CONDON, Primary Examiner.

JAMES R. GARRETT, Examiner. 

